5 Reasons Why Angelfish is Swimming at the Top

Here’s Why Your Angelfish is Swimming at the Top

Some of the most beautiful and spectacular fish you can have in a freshwater aquarium are Angelfish. They belong to the Cichlidae family and are native to South America. People love them for their long flowing fins, swimming behaviors and their colors.

Angels can live for up to ten years in a tank that has the right conditions. However, on occasion, you may see your fish acting strange and swimming around the top of the tank more than usual. There are a few reasons for this.

Here’s why your Angelfish is swimming at the top:

The main reasons Angelfish swim at the top are mainly to do with water quality, or they are searching for food. It may be a lack of oxygen, temperatures are out of line, the quality of water is poor, or there is a lack of aeration.

Read on, and we will go through the main reasons why your Angelfish may be swimming at the top of your tank. We will also show what you can do to correct this, so your fish remains happy and healthy.

angelfish in aquarium

1# Is My Angelfish Hungry?

Hunger can be one of the first things to eliminate quickly in your Angelfish. It is likely the least reason your fish is hovering toward the water’s surface, so getting this reason dismissed quickly gives you a chance to move on.

Being sure you are feeding your Angelfish, the right food is crucial. Angelfish are omnivores, so they are open to eating anything. However, they do require a diet that is high in fiber and proteins. In an aquarium setting, they should be eating the same kind of food they eat in the wild, such as small live prey.

Larvae, crustaceans and insects, as well as smaller fish, are what their diet comprises. While you may be feeding them flakes, a diet purely of this can lead them to have deficiencies, and they are looking for their natural foods.

You can spice up their diet by feeding them frozen or live foods. You can even feed them blanched vegetables every now and again, as long as you mash them with a fork. Freeze-dried foods come in a large variety, but krill and glass-worms are more than ideal.

2# Do You Have Poor Water Quality?

Poor water quality can stem from a few different reasons. One of the most common is the tank is overpopulated. Once this happens, it can be hard for filtration units to cope. Besides, you may have a filtration unit that isn’t performing as it should, or the filter is dirty and old.

If any of these instances arise, then there can be spikes in ammonia, nitrates and nitrites, which are all harmful to fish. Once you have filters that are not performing, or they are undersized, you will find fish waste, uneaten food, and plant debris fall to the bottom, and start to decay. All these will create these toxic elements.

Ammonia is the worst and can make fish feel their gills are burning. Hence, the reason they try to take oxygen from above the waterline. Check your filter, and clean or purchase one that can cope with a larger fish population or large tank.

3# Lack of Dissolved Oxygen

You will find a lack of dissolved oxygen is the main reason Angelfish start swimming at the top of the aquarium, as they attempt to breathe.

They need to absorb oxygen through their gills, and if this is lacking, they have to find it in areas that contain the most. In most instances, this is at the top of the tank. Like all gasses, oxygen rises, so the upper portions of your tank will hold the most.

The easy ways to address this are to add an air pump if you don’t already have one. Add to this an air stone, and you can quickly increase the amount of dissolved oxygen to the tank water. One other thing you can do is to purchase a test kit so you can test the oxygen levels. For reference, the levels need to be around 8 PPM for dissolved oxygen. On the safe side, you are better just having a good quality air pump and air stones.

Dissolved Oxygen

4# Water Temperatures are Too Hot or Too Cold

Temperatures on either side of the ideal can affect any fish. For Angelfish, it is usually the water temperatures are too warm. To escape the warmth, they can be seeking a way out from the surface, and gasping at the top is their way to try to achieve this.

Warm waters hold less dissolved oxygen than colder water so that it could be a combination with the above.

Cold waters can leave your Angelfish trying to find warmer water, and this is another reason they are at the top where warmer waters will be.

Ideal temperatures for your Angelfish are between 74 and 84 degrees Fahrenheit. You can keep a check on this by purchasing an aquarium thermometer, which is inexpensive and can save many heartaches if your aquarium temperatures fall outside of the ideal range for your fish.

Another consideration is if your water is continually on the cold or warmer end of the ideal range. You may need to consider an aquarium heater, and depending on your climate, it may be you require a tank chiller to maintain the typical temperatures.

5# Poor Aeration

Aeration links to the oxygenation of your water, although it is different. Oxygenation is the amount of dissolved oxygen in your water, while aeration is how far it spreads around your tank. Issues arise when there is little flow of water, and all the aeration forms where your air stone is, and then rises toward the surface.

If you have a water filter and water pump that is underpowered for your size of the tank, you will have dead areas that contain no oxygen.

This can be an easy fix, and all it requires is a more extensive water pump or device that can create water flow.

Does My Angelfish Need Bubbles?

Angelfish Need Bubbles

Out of the above reasons your Angelfish is swimming to the upper parts of your aquarium, it may sound like you need bubbles in your aquarium.

In reality, this isn’t the case if you are thinking of large bubbles. Dissolved oxygen is small bubbles, which you can’t see, and it is this, that is crucial.

The best ways to ensure you have enough dissolved oxygen is to keep many aquarium plants and a functional performing filtration unit. The best kind, are a power filter with waterfall, as this breaks the surface of the water to add more oxygen.


It can be worrying if you see your Angelfish sticking to the top of your tank. However, when you look at the above information, you can quickly see the remedy to the problem.

Lack of oxygen and aeration are common problems across many aquariums, and rectifying this can lead to happier fish. You will also see, resolving these two areas, your water quality will improve, and your tank overall will be a lot simpler to keep clean.

With one of two changes, your ‘King of the Aquarium’ will be back swimming around the tank rather than staying huddled at the top.